California catches crabs: Thousands of crustaceans wash ashore

Holy crab! The beaches of Southern California are red and crawling, as thousands of marine squat lobsters ‒ better known as pelagic red crabs or tuna crabs ‒ are taking the coastline by storm. Warm water conditions have caused the mass stranding.

Donna Kalez was walking along the beach in Orange County,
California, when she saw the beach teeming with small, red
crustaceans. More of them came in with every wave.

“They are all still alive. They are in the surfline and
swimming up,” Kalez told the Orange County Register.
“Once they get this close to shore, they can’t go anywhere,
so they just wash in. They aren’t strong enough to swim
out.”

"Once they are on the sand their life cycle has typically
come to an end," Marine Protection Officer Jeremy Frimond
told the Coastline Pilot. "However, some may still move
slightly as their death is not instant once beached."

But the circle of life has been a boon for gulls and crows, which
have feasted on the tuna crabs.

The three-inch-long tuna crabs’ ‒ scientific name Pleuroncodes
planipes ‒ normal habitat is the shallow waters on the
continental shelf west of Mexico, though they can be found as far
south as Chile.

"These animals move with ocean currents. Sporadically these
currents point the animals inshore and the result is what we have
been seeing on our beaches the past few days," Frimond said.

Experts believe this year's El Niño conditions ‒ bands of
abnormally warm water have swept up the Pacific Coast since the
waning months of 2014 ‒ might be responsible for the tuna crabs
appearance from San Diego up to Orange County.

"They have this ability to transition from the seafloor
through the water column," Linsey Sala, collection manager
at University of California San Diego's Scripps Institution of
Oceanography, told the Washington Post. "They're subject to
current and internal waves and tides, so they can be pushed along
with different water masses. Typically, when we do see larger
numbers of tuna crab, it's during warm water intrusions."

"It's been a really unusually warm year, and disruptive to
the normal marine food web, from Baja all the way up to
Alaska," Nate Mantua, a climatologist with NOAA's Southwest
Fisheries Science Center, told National Geographic.

A massive patch of warm water off the US West Coast called “the
blob” is also causing marine
life to appear in unusual places, as warm water with less
nutrients is disrupting ecosystems and food supply. The blob is
contributing to warmer-than-average drought conditions in
California, as well.

I think this is a healthy harbor seal pup waiting for its
fishing mother with some unhealthy by-the-wind sailors.
pic.twitter.com/0GESjUFPOr

In the spring, billions of small, bright blue jellyfish-like
animals ‒ called “by-the-wind sailors” ‒ washed ashore all along
the United States’ Pacific coastline, thanks to warmer water
bringing them far inland of their normal open-ocean habitat,
National Geographic reported in April. The mass strandings of
by-the-wind sailors happen every three to six years, according to
Kevin Raskoff, a marine biologist at Monterey Peninsula College
in central California.